The research program proposed in this competing renewal application consists of three closely interrelated and interdependent projects directed toward rigorous evaluation, utilization and refinement of a unique technique for localized and controllable heating of deep, as well as of extensive, intractable superficial tumors, combined with a technique for high density measurement of tissue temperature, perfusion and PO2. It represents logical continuation of the promising areas of the work presently being conducted. From studies during 670 sessions in 123 patients, the Scanned Intensity-Modulated Focused Ultrasound (SIMFU) system is found to be routinely capable of heating 10 cm x 10 cm x 10 cm tumors up to a depth of 12 cm to therapeutic temperatures, without toxicity to surrounding tissues. Confirmation of these data in a hospital setting and studies of clinical efficacy of local tumor hyperthermia alone or with drugs or radiation is the focus of the project to be conducted at the Dana Farber Cancer Institute. The other two projects are respectively aimed at further development, refinement, evaluation and integration of the SIMFU, and the thermal dosimetry systems.